Adrian Luckman

Iceberg A23a continues to break apart in the southern Atlantic Ocean, near the island of South Georgia.

We have a new preprint out reviewing the monitoring & detection of Svalbard surging glaciers: eartharxiv.org/repository/v...

We also compiled a new database of Svalbard's surge-type glaciers: zenodo.org/records/1524...

@dannipearce.bsky.social @hazlovell.bsky.social @adrianluckman.bsky.social

Check out this time-lapse video of waves eroding an ice front from an experiment conducted in our cryogenic wave tank at the University of Wisconsin-Madison. The tank is housed in a walk-in freezer, and the waves are precisely controlled. This video captures about an hour of wave erosion.

Iceberg A23a on 7/7/25 Eumetsat/Meteosat 12

In case you were wondering... Iceberg A23a seen cruising around South Georgia today by Meteosat 12. The old berg still has an area of 2,846 sq km.

Global average temperature compared with the middle of the 20th century +1.0°C 2010 to present +0.5°C 1970 to 2010 Cooler than average -0.5°C 1880 to 1970 • Note: Data available through May 2025. Anomalies relative to the average temperature between 1951 and 1980. • The New York Times 2020

I hope everyone on this website thinks very carefully about this graph and then considers whether or not they need to reorder their priorities at all.

Jakobshavn Isbrae (Ilulisat Glacier) produces 10% of Greenland's icebergs (Wikipedia). Ten years of @esa.int Copernicus #Sentinel-1 SAR data shows ice pouring into Baffin Bay. Winter advance and summer retreat of the ice front show how calving is controlled by seasonal freeze-up of fjord ice melange

PolarView 13/5/25

Sentinel-1 has finally got a clear view of iceberg A23a (13/6/25). The berg is much diminished as it skirts around South Georgia. And the US National Ice Center has updated its stats: A23a is now only the world's second biggest berg at 829.79 sqNM, or 2846,11 sqKM.

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Nested glacier surges! This is Liestolbreen in Svalbard, surging into Nathorstbreen (which itself surged from 2008), and then being surged into by Doktorbreen. All brought to you by the magic of Sentinel-1 SAR

The movement of iceberg A23a over the past seven days. It's moved about 80km to the southeast of the position where it grounded off the coast of South Georgia in early March. Zoomed in animation from Meteosat-12.

Meteosat view of South Georgia and iceberg A23a. 30/5/25

With days shortening at South Georgia (it's about 8 hours from sunrise to sunset), optical satellite coverage in the region is getting more restricted. Not so for Meteosat, which images the Europe/Africa hemisphere regardless of season. Hence we get a few views of iceberg A23a. Still grounded.

Iceberg A23a on 3 May. Copernicus / Sentinel-3

There was a spectacular view of iceberg A23a on 3 May. Clear skies over the berg and South Georgia. By my measurement, A23a is no longer the world's biggest iceberg. At ~2850 sq km, it's now bested by D15a - but only just. The US National Ice Center will be the final judge on the matter.

The journey of Iceberg A23a (largest, oldest, 'living' berg) since the beginning of 2024, as seen by NASA MODIS, including its five-month pirouette on the Taylor Column, short embrace by the pack ice in August, grounding on South Georgia's shelf in April, and baby calf. Watch this space for updates!

Large fractures continue to open up at the grounding line of Thwaites Glacier Eastern Ice Shelf. Animation contains @copernicusland.bsky.social #Sentinel-1C data alongside 1A and 1B

A23a and A23c pictured off South Georgia on 22/4/25 Nasa Worldview Modis

US National Ice Center formally catalogues A23c, the big off-cut from grounded behemoth A23a. Daughter berg is ~130km² - or 2x Manhattan Island. A23a (~3,100km²) only needs to lose another ~30km² to hand "World's Biggest Iceberg" title to D15a (~3,070km²) in Amery Sea.

Sentinel-3 Copernicus Data.

A big chunk has broken away from iceberg A23a, currently grounded at South Georgia. I calculate ~110 sq km. Looks to have fractured sometime on 11/12 April. It will get a US National Ice Center designation. It should be A23c, unless I'm mistaken.

Kronebreen is one of the fastest flowing glaciers in Svalbard. Ten years of @esa.int #Sentinel-1 data shows us both the annual advance/retreat cycle characteristic of melt-undercut calving in a seasonally warmed fjord, and the long-term retreat caused by climate warming. Email me for hi-res version

So sorry for the typo Noel Gourmelen!

YouTube video by European Space Agency, ESA How subglacial lakes threaten Antarctic Ice Sheet stability

Fantastic new animation from ESA featuring CryoSat-2 & Sentinel-1 animations, highlighting our Nature-Comms paper "The influence of subglacial lake discharge on Thwaites Glacier ice-shelf melting and grounding-line retreat" www.nature.com/articles/s41... led by Noel Gourmelan: youtu.be/vRMeiMsQkBE

Map depicting Helheim Glacier comprised of grey-scale backscatter image overlain by colours from blue to pink denoting ice surface velocity from 2 to 30 meters per day during the period 25th to 31st March 2025

So exciting! Sentinel-1C (launched December) is finally delivering data to users and we can get back to exploring 6-day-repeat interferometry and feature-tracking such as this lovely new velocity map of Helheim Glacier in East Greenland. Nice one Copernicus!

NASA/JPL/Caltech/ARIA/Copernicus Product. POC: R Zinke/G Bato/C Speed/E Fielding.

You don't need to be a seismologist to look at this figure and understand the huge forces that ripped through Myanmar on March 28. The M7.7 quake ruptured fully 500km of the Sagaing Fault, moving its western flank north, with >3m of slip at the surface. Data from EU Sentinel satellites.

Update on Thwaites Glacier Eastern Ice Shelf from Copernicus Sentinel-1 SAR. Downloadable version here: aluckman4.wixsite.com/ade-s-world-...

NASA/JSC/ISS

Iceberg A23a pictured from the ISS. The space station is almost as far south as it can reach here (51.5° S, 49.0° W - altitude of 422km). Picture taken on 14 March, so the berg had been grounded at South Georgia for a fortnight by this time.

As polar night ends and sunlight begins to return to Longyearbyen, lets see how the Svalbard seasons progressed last year - from ice-locked fjords in March, through to the first snows of October. Thanks to NASA MODIS via GIBS. Download at full resolution here: aluckman4.wixsite.com/ade-s-world-...

Europe had its least snowy winter (Dec-Feb) in over 50 years. #ThisIsFine

Line graph time series of 2025's daily global sea ice extent in red shading compared to each year from 1979 to 2024 using shades of purple to white for each line for between the months of January and April. The year 2023 is also highlighted in yellow, which was the current absolute record low previously. There is substantial interannual and daily variability.

The extent of sea ice around the world continues to remain the smallest in our satellite observation history for this time of year...

More graphs at zacklabe.com/global-sea-i.... Data from @nsidc.bsky.social.

A map of the recent positions of iceberg A23a from 17th Jan - 3rd March 2025. Bathymetry is shown on the map, with shallow shelf areas indicating where the iceberg is stuck on the seafloor.

A map showing the track of iceberg A23a from calving (breaking off) the Filchner Ice Shelf in 1986, to its most recent position SW of South Georgia. The track is shown with purple dots. Bathymetry is shown with a blue colour ramp.

The world's largest iceberg, A23a, appears to have grounded close to South Georgia. We've been monitoring and mapping this berg for many years now and we're watching closely to see what it might do next! These maps show its route since 1986 and the latest position to the SW of South Georgia ❄️🐧
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Rain in the northernmost city on Earth. This month temperatures have been almost always above normal.

The Arctic is becoming totally unrecognisable.

And in the meantime #BP and #Equinor are doubling down on fossil fuels.

Profits over people. Profits over a liveable Earth.

Pisgana West (Adamello, IT)
1990 | 2021

Remember the 1990s? ⌚️❄️
Seems so far away from a glaciological point of view! 😱

And the most recent pic here was taken before the recent record-breaking heatwaves which wiped out 10% of Alpine ice in just 2 years! 🔥

📷 Servizio Glaciologico Lombardo

Pine Island Glacier accounts for a large proportion of recent Antarctic ice loss. This 7.5 year animation from Sentinel-1 shows the weakening of the lateral margins and the stochastic nature of the calving process. Grab a full-screen version here: aluckman4.wixsite.com/ade-s-world-...